add a failing test for case-sensitive CHANGELOG

src/prepare.test.ts

@@ -46,4 +46,36 @@ thing v1.0.0 (major)
 `);
     });
   });
+
+  it('updates changelog correctly with case insensitive CHANGELOG', function () {
+    mocks.readFileSync.mockReturnValue(`# A Totally ficticious CHANGELOG
+
+## Some Old version
+
+- added some features
+- spent a lot of time trying to figure out releases (if only there was a tool to help with that)
+`);
+    updateChangelog(
+      `## v1.0.0
+
+- added release-plan (how did I live without it!?)
+- releasing initial working version`,
+      new Map([['thing', { newVersion: 'v1.0.0', impact: 'major' }]]) as any,
+    );
+    const [, newChangelog] = mocks.writeFileSync.mock.lastCall;
+    expect(newChangelog).to.eq(`# A Totally ficticious Changelog
+## v1.0.0
+
+thing v1.0.0 (major)
+
+- added release-plan (how did I live without it!?)
+- releasing initial working version
+
+## Some Old version
+
+- added some features
+- spent a lot of time trying to figure out releases (if only there was a tool to help with that)
+`);
+  });
+
 });